Anyone who has grown up in a large family knows only too well the tears, rows and constant battles for their parents' attention.

And now scientists believe the size of a family really can affect the behaviour and achievements of children.

A new study has found that for every additional child born, the others are more likely to suffer poor cognitive abilities and behavioural problems afterwards.

Boys were more likely to misbehave while girls saw their performance in maths and reading skills dip.

The study found that for every additional child born, the others are more likely to suffer poor cognitive abilities and behavioural problems afterwards (file photos)

Using data from 1986 to 2012 taken by the National Longitudinal Survey of Youth (NLSY) and by the Children and Young Adult Survey, three economists analysed how older siblings performed before and after a younger sibling was born.

They looked at the number and timing of births into a family and matched these to various mental and behavioural traits.

Levels of parental engagement were also crucial - with factors like how often families eat meals together, one-on-one time with each child, affection and the safety of the home also affecting how a child performed.

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As families got bigger, the time spent with each child reduced, which has been linked to worse outcomes for children, they found.

'Our fixed effect estimates indicate that the arrival of a younger sibling reduces measures of parental investment as well as cognitive and non-cognitive outcomes of older children by approximately one-tenth of a standard deviation,' the research paper said.

The study was conducted by economists Chinhui Juhn, Yona Rubinstein, and C. Andrew Zuppann, who questioned whether the 'quantity' of children would effect the 'quality' of their upbringing.

It discovered that parental investment in older kids fell by 3 percentile points after a young child is born, while cognitive scores fell by 2.8 percentile points and behavioural problems increased.

Boys were more likely to misbehave while girls saw their performance in maths and reading skills dip

'We have documented a significant trade-off between quantity and quality of children for NLSY mothers and their children.

Other factors found to influence the outcomes was the mother's intelligence and economic well-being.

On average, children in larger families have lowered parental investment and worse cognitive and non-cognitive outcomes

Mothers were asked to take the Armed Force Qualification Test (AFQT), used by the military to assess skills including reading and reasoning.

Those who scored badly saw a larger drop in cognitive scores when they had their second child.

The study follows another by German researchers which found the first-born in a family tends to be the smartest – and each successive sibling is slightly less bright.

The Leipzig University researchers were unsure why big brothers and sisters seemed to be the most blessed - but suggested it could be because they benefit from their parents’ undivided attention – at least until a little brother or sister comes along.

It is also possible that the eldest child’s brainpower gets a boost from teaching his or her siblings about the ways of the world, they said.

Other factors that were found to affect children's performances were the amount of meals shared as a family and how much time was spent with each child